Questions? Contact
health@NEMDA.org
American College of
Veterinary Ophthalmologists
Find ACVO Clinic
Canine Eye Registration
Foundation – CERF
Orthopedic Foundation
For Animals – OFA
Animal Poison
Control Center – ASPCA
PennHIP Method
CHD is an inherited disease which results in painful changes to the hip joint due to the lack of proper conformation and articulation between the head of the femur and the socket. If the joint is not properly formed, then there may be abnormal bone growth, joint capsule thickening, joint distension and laxity, rear limb lameness, and pain. It is known that multiple genes have been found to contribute to the size, shape, strength, and growth potential of the hip joint. The severity of the disease is determined by the number of disease related genes present in each dog. Environmental factors can also significantly affect the degree that the condition is manifested.
Breeders and veterinarians have sought a reliable method of determining the likelihood of a dog developing CHD, and passing that trait on to offspring. The University of Pennsylvania School of Veterinary Medicine has developed a scientific method for the early diagnosis of CHD. The University of Pennsylvania Hip Improvement Program (PennHIP) was founded to evaluate dogs as young as sixteen weeks for susceptibility to develop Degenerative Hip Disease (DJD). PennHIP is a radiographic procedure which accurately measures the “passive hip laxity,” an important factor in determining the susceptability to develop DJD. Passive hip laxity refers to the degree of looseness of the hip ball in the hip socket when the dog’s muscles are completely relaxed.
The PennHIP method specifically measures the degree of hip joint laxity and reports it as a quantitative measurement, and then ranks the dog relative to other members of the same breed. (Note: Breed specific rankings require 20 or more evaluations. If there are fewer than 20, then the ranking is made to the general dog population.) As an example, if a dog were rated in the 80th percentile, then 20% of its breed members have hips that are tighter. It has been proven that dogs with tighter hips are less likely to develop CHD, so breeders can easily use this method to find the dogs with tighter hips to use for breeding purposes.
In a PennHIP evaluation, the dog is sedated to enable the hip muscles to be completely relaxed. Three radiographs are made during an evaluation. The first is a compression view in which the balls of the femurs are pushed fully into the sockets in order to show the depth of the hip socket. The second is a distraction view in which a special positioning device is used to cause the hips to gently displace laterally. This view shows the degree of passive laxity which has been shown to correlate with the susceptability of developing DJD. The third is a hip extended view which is examined for any existing signs of joint disease.
The PennHIP method can accurately predict the susceptibility to developing CHD in dogs as young as sixteen weeks. This early detection will enable an owner to provide treatment for an affected dog before arthritic changes occur. Breeders can determine at an earlier age whether their dog is of breeding potential, which would enable earlier spay/neuter if DJD were found. The PennHIP data will allow breeders to confidently identify members of their breeding stock with the tightest hips and to assess the progress that they are making with their breeding program. Pet owners can assess their pet’s risk of developing CHD and seek treatments which would enhance the quality of life for their dog.
To obtain the name of a veterinarian near you who is trained and qualified to perform the PennHIP procedure, see the PennHIP web site, or contact ICG at 1 (800) 248-8099. You may also contact the NEMDA Genetics chair, Teri Beeman, for more information.